CN109873163B

CN109873163B - Current collector, pole piece and battery thereof and application

Info

Publication number: CN109873163B
Application number: CN201711267487.XA
Authority: CN
Inventors: 梁成都; 黄华锋; 黄起森
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2017-12-05
Filing date: 2017-12-05
Publication date: 2021-07-06
Anticipated expiration: 2037-12-05
Also published as: CN109873163A; JP2019102425A; EP3506403A1; JP6858735B2; US11024854B2; PT3506403T; US20190173089A1; EP3506403B1; HUE062079T2

Abstract

The application relates to the field of batteries, in particular to a current collector, a pole piece thereof, a battery and application. The current collector comprises an insulating layer with a supporting function, a conducting layer with a conducting and current collecting function and a normal-temperature film resistor R of the conducting layer_SSatisfies the following conditions: r is more than or equal to 0.01 omega/□_SLess than or equal to 0.15 omega/□. The current collector can greatly improve the short-circuit resistance when the short circuit occurs under the abnormal condition of the battery, so that the short-circuit current is greatly reduced, the short-circuit heat generation quantity can be greatly reduced, and the safety performance of the battery is greatly improved; in addition, because the heat generation amount is small, the heat generated at the position of the internal short circuit can be completely absorbed by the battery, and the temperature rise of the battery is small, so that the influence of the short circuit damage on the battery is limited to a 'point' range, and only 'point open circuit' is formed, and the normal work of the battery in a short time is not influenced.

Description

Current collector, pole piece and battery thereof and application

Technical Field

The application relates to the field of batteries, in particular to a current collector, a pole piece thereof, a battery and application.

Background

Lithium ion batteries are widely used in electric vehicles and consumer electronics because of their advantages of high energy density, high output power, long cycle life, and low environmental pollution. However, the lithium ion battery is easily ignited and exploded when being subjected to abnormal conditions such as extrusion, collision or puncture, thereby causing serious damage. The safety issues of lithium ion batteries have thus largely limited their application and popularity.

A large number of experimental results show that the short circuit in the battery is the root cause of the potential safety hazard of the lithium ion battery. In order to avoid the occurrence of short circuits in the battery, researchers have attempted to improve the separator structure, the mechanical structure of the battery, and the like. Some of these studies are directed to improving the safety performance of lithium ion batteries in terms of improving the design of current collectors.

When the battery is internally short-circuited due to abnormal conditions such as collision, extrusion, puncture and the like, the temperature of the battery rises; the prior art adopts the technical scheme that low-melting-point alloy is added into the material of a metal current collector, and the low-melting-point alloy in the current collector is melted along with the rise of the temperature of the battery, so that the pole piece is disconnected, the current is cut off, and the safety of the battery is improved; or a current collector with a multilayer structure with metal layers compounded on both surfaces of the resin layer is adopted, and when the temperature of the battery rises and reaches the melting point of the material of the resin layer, the resin layer of the current collector is melted to damage the pole piece, so that the current is cut off, and the safety problem of the battery is improved.

However, these methods in the prior art cannot effectively prevent the occurrence of short circuit in the lithium ion battery, and cannot ensure that the battery can continue to operate after abnormal conditions occur. In these improved methods, after the internal short circuit of the battery occurs, the battery temperature still rises sharply, and when the battery temperature rises sharply, if the safety member cannot respond quickly, risks still occur to various degrees; in these improved methods, the safety hazard of the battery is solved after the safety member responds, but the battery cannot continue to operate.

Therefore, it is necessary to provide a current collector and a battery design that can effectively prevent accidents such as fire and explosion of the battery due to occurrence of internal short circuit after abnormal conditions such as collision, extrusion, puncture, etc. occur, without affecting the normal operation of the battery.

Disclosure of Invention

In view of this, the present application provides a current collector, a pole piece and a battery thereof, and applications thereof.

In a first aspect, the present application provides a current collector; the insulating layer is used for bearing the conducting layer; the conducting layer is used for bearing an electrode active material layer and is positioned on at least one surface of the insulating layer, and the normal-temperature thin-film resistor R of the conducting layer_SSatisfies the following conditions: r is more than or equal to 0.01 omega/□_S≤0.15Ω/□。

In a second aspect, the present application proposes the use of this current collector in the preparation of a battery which, when subjected to an abnormal condition which induces a short circuit, forms only a point-break to protect itself.

In a third aspect, the present application proposes the use of the current collector as a current collector for a battery that, when subjected to an abnormal condition that causes a short circuit, forms only a point disconnection.

In a fourth aspect, the present application provides a pole piece comprising the current collector of the first aspect.

In a fifth aspect, the present application provides a battery comprising the pole piece of the fourth aspect.

The technical scheme of the application has at least the following beneficial effects:

the application provides a mass flow body, this mass flow body including the insulating layer that has supporting role and the conducting layer that has electrically conductive and current collection effect, the normal atmospheric temperature sheet resistance R of conducting layer_SSatisfies the following conditions: r is more than or equal to 0.01 omega/□_SLess than or equal to 0.15 omega/□. The current collector can greatly improve the short-circuit resistance when the short circuit occurs under the abnormal condition of the battery, so that the short-circuit current is greatly reduced, the short-circuit heat generation quantity can be greatly reduced, and the safety performance of the battery is greatly improved; in addition, because the heat generation amount is small, the heat generated at the position of the internal short circuit can be completely absorbed by the battery, and the temperature rise of the battery is small, so that the influence of the short circuit damage on the battery is limited to a 'point' range, and only 'point open circuit' is formed, and the normal work of the battery in a short time is not influenced. The current collector's of this application conducting layer can also include the conducting layer body and be located the protective layer on at least one surface of conducting layer body to can improve this current collector's job stabilization nature and life greatly.

Moreover, the battery with the current collector can be damaged by multiple internal short circuits simultaneously or continuously, accidents such as fire and explosion do not occur, and the battery can normally work in a short time. In addition, the current collector with the normal-temperature film resistance of the conducting layer within the range has excellent safety performance, and can enable the battery to have good discharge capacity, rate performance and other electrochemical performances.

Drawings

Fig. 1 is a schematic structural view of a positive electrode current collector according to an embodiment of the present disclosure;

fig. 2 is a schematic structural view of a positive electrode current collector according to yet another embodiment of the present application;

fig. 3 is a schematic view of a negative current collector according to an embodiment of the present disclosure;

fig. 4 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

fig. 5 is a schematic structural view of a positive electrode current collector according to yet another embodiment of the present application;

fig. 6 is a schematic structural view of a positive electrode current collector according to yet another embodiment of the present application;

fig. 7 is a schematic structural view of a positive electrode current collector according to yet another embodiment of the present application;

fig. 8 is a schematic structural view of a positive electrode current collector according to yet another embodiment of the present application;

fig. 9 is a schematic structural view of a positive electrode current collector according to yet another embodiment of the present application;

fig. 10 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

fig. 11 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

fig. 12 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

fig. 13 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

fig. 14 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

fig. 15 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

fig. 16 is a schematic view of the structure of a negative electrode current collector according to yet another embodiment of the present application;

FIG. 17 is a schematic structural diagram of a positive electrode tab according to an embodiment of the present disclosure;

FIG. 18 is a schematic structural view of a positive electrode tab according to yet another embodiment of the present application;

FIG. 19 is a schematic view of a negative electrode tab according to an embodiment of the present disclosure;

FIG. 20 is a schematic structural view of a negative electrode tab according to yet another embodiment of the present application;

FIG. 21 is a schematic view of a single nailing experiment of the present application;

FIG. 22 is a graph showing the temperature change of batteries 1# and 4# after a single nail penetration test;

FIG. 23 is a graph showing the voltage change of batteries 1# and 4# after a single nail penetration test;

wherein:

1-positive pole piece;

10-positive current collector;

101-a positive electrode insulating layer;

102-a positive conductive layer;

1021-positive conductive layer body;

1022 — a positive electrode protective layer;

11-positive electrode active material layer;

2-negative pole piece;

20-a negative current collector;

201-negative electrode insulating layer;

202-a negative conductive layer;

2021-negative conductive layer body;

2022-negative electrode protective layer;

21-a negative active material layer;

3-a separator;

4-nails.

Detailed Description

The present application is further illustrated with reference to specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present application.

The embodiment of the application provides a current collector, which comprises an insulating layer and a conducting layer. The insulating layer is used for bearing the conductive layer and plays a role in supporting and protecting the conductive layer; the conductive layer is used for bearing the electrode active material layer and supplying electrons to the electrode active material layer, namely, the conductive layer plays a role in conducting and collecting current; the conductive layer is on at least one surface of the insulating layer.

Fig. 1 and 2 are schematic structural diagrams of a positive electrode current collector according to an embodiment of the present application, and as shown in fig. 1 and 2, a positive electrode current collector 10 includes a positive electrode insulating layer 101 and a positive electrode conductive layer 102 for coating a positive electrode active material to prepare a positive electrode sheet. Fig. 3 and 4 are schematic structural diagrams of a negative electrode current collector according to an embodiment of the present application, and as shown in fig. 3 and 4, the negative electrode current collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202 for coating a negative electrode active material to prepare a negative electrode tab. As shown in fig. 1 and 3, the insulating layer may be provided with a conductive layer on both of the opposite surfaces thereof, or as shown in fig. 2 and 4, a conductive layer may be provided on only one surface of the insulating layer.

The structure and performance of the current collector of the embodiments of the present application are described in detail below.

[ conductive layer ]

In the current collector of the embodiment of the application, the normal temperature sheet resistance R of the conductive layer_SSatisfies the following conditions: r is more than or equal to 0.01 omega/□_S≤0.15Ω/□。

In which the sheet resistance of the conductive layer is measured in ohms/square (Ω/□), may be applied to a two-dimensional system that considers the conductive body as a two-dimensional entity, which is equivalent to the concept of resistivity used in a three-dimensional system. When using the concept of sheet resistance, the current is theoretically assumed to flow along the plane of the sheet.

For a conventional three-dimensional conductor, the formula for the resistance is:

where ρ represents the resistivity, a represents the cross-sectional area, and L represents the length. The cross-sectional area can be decomposed into a width W and a film thickness t, i.e., the resistance can be written as:

wherein R is_SNamely the film resistor. When the diaphragm is square, L ═ W, the measured resistance R is the sheet resistance R of the diaphragm_SAnd R is_SIndependent of the size of L or W, R_SIs the resistance value of the unit square, therefore R_SThe units of (d) may be expressed in ohms per square (Ω/□).

The normal-temperature film resistor in the embodiment of the application refers to a resistance value measured by a four-probe method on the conductive layer under a normal temperature condition, wherein the normal temperature is 15-25 ℃.

In the conventional lithium ion battery, when a short circuit occurs in the battery under abnormal conditions, a large current is instantaneously generated, and heat is generated along with the large short circuit, and the heat usually causes thermite reaction at a positive electrode aluminum foil current collector, so that the battery is ignited, exploded and the like. In the embodiment of the application, the normal-temperature film resistance R of the current collector is improved_SThereby solving the technical problem.

The internal resistance of the battery generally comprises ohmic internal resistance of the battery and polarization internal resistance of the battery, wherein the internal resistance of the battery is obviously influenced by active material resistance, current collector resistance, interface resistance, electrolyte composition and the like.

When a short circuit occurs in an abnormal situation, the internal resistance of the battery is greatly reduced due to the occurrence of the internal short circuit. Therefore, the resistance of the current collector is increased, and the internal resistance of the battery after short-circuiting can be increased, thereby improving the safety performance of the battery. In the embodiment of the application, when the battery can limit the influence of short-circuit damage on the battery to the range of points, the influence of the short-circuit damage on the battery can be limited to the position of the damaged point, the short-circuit current is greatly reduced due to the high resistance of the current collector, the temperature rise of the battery is not obvious due to the heat generated by short circuit, and the characteristic that the normal use of the battery in a short time is not influenced is called point disconnection.

When the normal temperature film resistance R of the conductive layer_SSatisfies the following conditions: r is more than or equal to 0.01 omega/□_SWhen the voltage is less than or equal to 0.15 omega/□, the short-circuit current can be greatly reduced under the condition that the battery is internally short-circuited, so that the short-circuit heat generation quantity can be greatly reduced, and the safety performance of the battery is greatly improved; in addition, the heat generated by the short circuit can be controlled within the range which can be completely absorbed by the battery, so that the heat generated at the position of the internal short circuit can be completely absorbed by the battery, and the temperature rise caused to the battery is causedAnd is small, so that the influence of short-circuit damage on the battery can be limited to a 'point' range, and only a 'point open circuit' is formed, and the normal operation of the battery in a short time is not influenced.

Optionally, a normal temperature sheet resistor R of the conductive layer_SSatisfies the following conditions: r is more than or equal to 0.02 omega/□_S≤0.1Ω/□。

When the normal temperature film resistance R of the conductive layer_SIf the size of the conductive layer is too large, the effects of the conductivity and the current collection of the conductive layer are affected, electrons cannot be effectively conducted among the current collector, the electrode active material layer and the interface of the current collector and the electrode active material layer, namely, the polarization of the electrode active material layer on the surface of the conductive layer is increased, and the electrochemical properties of the battery, such as the discharge capacity, the rate performance and the like, are affected. Therefore, the normal temperature film resistance R of the conductive layer_SSatisfies the following conditions: r is more than or equal to 0.01 omega/□_S≤0.15Ω/□。

In the present application, the room temperature sheet resistance R_SThe upper limit of the resistance can be 0.15 omega/□, 0.12 omega/□, 0.1 omega/□, 0.09 omega/□, 0.08 omega/□, 0.07 omega/□ and 0.05 omega/□, and the room-temperature sheet resistance R can be_SThe lower limit of (B) can be 0.01. omega./□, 0.02. omega./□, 0.025. omega./□, 0.03. omega./□, 0.04. omega./□; film resistor R at normal temperature_SA range of (B) may consist of any number of upper or lower limits.

In addition, the thickness of the conductive layer also has a large impact on the operational reliability and operational life of the current collector according to the present application.

Preferably, in the current collector of the embodiment of the present application, the thickness of the conductive layer is D2, and D2 satisfies that: d2 is more than or equal to 300nm and less than or equal to 2 mu m. If the conductive layer is too thin, it is beneficial to increase the sheet resistance R of the current collector at room temperature_SBut is easy to be damaged in the processes of pole piece processing technology and the like; if the conductive layer is too thick, it will affect the weight energy density of the battery and will not contribute to increasing the normal temperature sheet resistance R of the conductive layer_S。

Wherein the upper limit of the thickness D2 of the conductive layer can be 2 μm, 1.8 μm, 1.5 μm, 1.2 μm, 1 μm, 900nm, 800nm, 700nm, 600nm, 500nm, and the lower limit of the thickness D2 of the conductive layer can be 300nm, 350nm, 400nm, 450 nm; the range of the thickness D2 of the conductive layer may consist of any value of the upper or lower limit. Preferably 500 nm. ltoreq. D2. ltoreq.1.5 μm.

Optionally, the material of the conductive layer is selected from at least one of a metal conductive material and a carbon-based conductive material. Wherein, the metal conductive material is preferably at least one of aluminum, copper, nickel, titanium, silver, nickel-copper alloy and aluminum-zirconium alloy; the carbon-based conductive material is preferably at least one of graphite, acetylene black, graphene and carbon nanotubes.

Wherein the conductive layer can be formed on the insulating layer by at least one of mechanical rolling, bonding, Vapor Deposition (PVD), and Electroless plating, and the PVD is preferably Physical Vapor Deposition (PVD); the physical vapor deposition method is preferably at least one of an evaporation method and a sputtering method; the Evaporation method is preferably at least one of vacuum Evaporation (vacuum Evaporation), Thermal Evaporation (Thermal Evaporation) and Electron Beam Evaporation (EBEM), and the sputtering method is preferably Magnetron sputtering (Magnetron sputtering).

Further, the conductive layer of the current collector of the embodiment of the present application may include a conductive layer body and a protective layer on at least one surface of the conductive layer body. The protective layer can prevent the conductive layer body from being oxidized, corroded or damaged, so that the working stability and the service life of the current collector can be greatly improved.

Fig. 5 to 12 are schematic structural diagrams of a current collector provided with a protective layer according to an embodiment of the present application. Schematic diagrams of the positive electrode current collector are shown in fig. 5 to 10.

In fig. 5, the positive electrode collector 10 includes a positive electrode insulating layer 101 and positive electrode conductive layers 102 disposed on opposite surfaces of the positive electrode insulating layer 101, and the positive electrode conductive layers 102 include a positive electrode conductive layer body 1021 and a positive electrode protective layer 1022 disposed on a surface of the positive electrode conductive layer body 1021 facing away from the positive electrode insulating layer 101 (i.e., an upper surface of the positive electrode conductive layer body 1021).

In fig. 6, the positive electrode collector 10 includes a positive electrode insulating layer 101 and positive electrode conductive layers 102 disposed on opposite surfaces of the positive electrode insulating layer 101, and the positive electrode conductive layers 102 include a positive electrode conductive layer body 1021 and a positive electrode protective layer 1022 disposed on a surface of the positive electrode conductive layer body 1021 facing the positive electrode insulating layer 101 (i.e., a lower surface of the positive electrode conductive layer body 1021).

In fig. 7, the positive electrode collector 10 includes a positive electrode insulating layer 101 and positive electrode conductive layers 102 disposed on opposite surfaces of the positive electrode insulating layer 101, and the positive electrode conductive layers 102 include a positive electrode conductive layer body 1021 and positive electrode protective layers 1022 disposed on opposite surfaces of the positive electrode conductive layer body 1021 (i.e., upper and lower surfaces of the positive electrode conductive layer body 1021).

In fig. 8, the positive electrode collector 10 includes a positive electrode insulating layer 101 and a positive electrode conductive layer 102 disposed on one surface of the positive electrode insulating layer 101, and the positive electrode conductive layer 102 includes a positive electrode conductive layer body 1021 and a positive electrode protective layer 1022 disposed on a surface of the positive electrode conductive layer body 1021 facing away from the positive electrode insulating layer 101 (i.e., an upper surface of the positive electrode conductive layer body 1021).

In fig. 9, the positive electrode collector 10 includes a positive electrode insulating layer 101 and a positive electrode conductive layer 102 disposed on one surface of the positive electrode insulating layer 101, and the positive electrode conductive layer 102 includes a positive electrode conductive layer body 1021 and a positive electrode protective layer 1022 disposed on one surface of the positive electrode conductive layer body 1021 facing the positive electrode insulating layer 101 (i.e., a lower surface of the positive electrode conductive layer body 1021).

In fig. 10, the positive electrode collector 10 includes a positive electrode insulating layer 101 and a positive electrode conductive layer 102 disposed on one surface of the positive electrode insulating layer, and the positive electrode conductive layer 102 includes a positive electrode conductive layer body 1021 and positive electrode protective layers 1022 disposed on opposite surfaces of the positive electrode conductive layer body 1021 (i.e., upper and lower surfaces of the positive electrode conductive layer body 1021).

Likewise, schematic views of the negative electrode collector are shown in fig. 11 to 16.

In fig. 11, the negative electrode current collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202 disposed on two opposite surfaces of the negative electrode insulating layer 201, and the negative electrode conductive layer 202 includes a negative electrode conductive layer body 2021 and a negative electrode protective layer 2022 disposed on a surface of the negative electrode conductive layer body 2021 facing away from the negative electrode insulating layer 201 (i.e., an upper surface of the negative electrode conductive layer body 2021).

In fig. 12, the negative electrode collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202 disposed on opposite surfaces of the negative electrode insulating layer 201, and the negative electrode conductive layer 202 includes a negative electrode conductive layer body 2021 and a negative electrode protective layer 2022 disposed on a surface of the negative electrode conductive layer body 2021 facing the negative electrode insulating layer 201 (i.e., a lower surface of the negative electrode conductive layer body 2021).

In fig. 13, the negative electrode current collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202 disposed on opposite surfaces of the negative electrode insulating layer 201, and the negative electrode conductive layer 202 includes a negative electrode conductive layer body 2021 and negative electrode protection layers 2022 disposed on opposite surfaces of the negative electrode conductive layer body 2021 (i.e., upper and lower surfaces of the negative electrode conductive layer body 2021).

In fig. 14, the negative electrode current collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202 disposed on one surface of the negative electrode insulating layer 201, and the negative electrode conductive layer 202 includes a negative electrode conductive layer body 2021 and a negative electrode protective layer 2022 disposed on a face of the negative electrode conductive layer body 2021 facing away from the negative electrode insulating layer 201 (i.e., an upper surface of the negative electrode conductive layer body 2021).

In fig. 15, the negative electrode collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202 disposed on one surface of the negative electrode insulating layer 201, and the negative electrode conductive layer 202 includes a negative electrode conductive layer body 2021 and a negative electrode protective layer 2022 disposed on a surface of the negative electrode conductive layer body 2021 facing the negative electrode insulating layer 201 (i.e., a lower surface of the negative electrode conductive layer body 2021).

In fig. 16, the negative electrode current collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202 disposed on one surface of the negative electrode insulating layer 201, and the negative electrode conductive layer 202 includes a negative electrode conductive layer body 2021 and negative electrode protective layers 2022 disposed on opposite surfaces of the negative electrode conductive layer body 2021 (i.e., upper and lower surfaces of the negative electrode conductive layer body 2021).

Optionally, the protective layer is located on a lower surface of the conductive layer body, i.e., between the conductive layer body and the insulating layer. The protective layer located at the position can protect the conductive layer body, so that the service life and the working reliability of the current collector are improved, and the current collector has the following advantages: (1) compared with the protective layer positioned on the upper surface of the conductive layer body, the protective layer positioned on the lower surface of the conductive layer body has stronger bonding force with the conductive layer body, and can play a role in protecting the conductive layer body; (2) the protective layer positioned on the lower surface of the conductive layer body can better enhance the mechanical strength of the current collector; (3) the protective layer on the lower surface of the conductive layer body can form a complete supporting structure to protect the conductive layer body.

Optionally, the protective layers are located on two opposite surfaces of the conductive layer body, i.e., the upper surface and the lower surface of the conductive layer body, thereby maximally improving the operational stability and the service life of the current collector, and improving the capacity retention rate, the cycle life, and the like of the battery.

The material of the conductive layer body is at least one selected from a metal conductive material and a carbon-based conductive material. The metal conductive material can be selected from at least one of aluminum, copper, nickel, titanium, silver, nickel-copper alloy and aluminum-zirconium alloy, and the carbon-based conductive material can be selected from at least one of graphite, acetylene black, graphene and carbon nano tubes.

The material of the protective layer may be at least one selected from the group consisting of metal, metal oxide, and conductive carbon. Optionally, the metal is selected from at least one of nickel, chromium, nickel-based alloys (such as nichrome), and copper-based alloys (such as cupronickel); optionally, the metal oxide is at least one selected from alumina, cobalt oxide, chromium oxide and nickel oxide; optionally, the conductive carbon is selected from at least one of conductive carbon black, carbon nanotubes, acetylene black, and graphene.

Wherein, the nickel-based alloy is an alloy formed by adding one or more other elements into pure nickel as a matrix. Preferably, the nickel-chromium alloy is an alloy formed by metal nickel and metal chromium, and the molar ratio of nickel element to chromium element is 1: 99-99: 1.

the copper-based alloy is an alloy formed by adding one or more other elements into pure copper serving as a matrix. Preferably a copper-nickel alloy, and optionally, the molar ratio of nickel element to copper element in the copper-nickel alloy is 1: 99-99: 1.

the materials of the protective layers on the two opposite surfaces of the conductive layer body may be the same or different and the thicknesses may be the same or different.

The thickness of the protective layer is D3, and when D3 is less than or equal to 1/10D2, the influence of the protective layer on the normal-temperature sheet resistance of the conductive layer can be ignored.

As a further improvement of the current collector of the embodiment of the application, the thickness of the protective layer is D3, and D3 satisfies: d3 is not less than 1/10D2, D3 is not less than 1nm and not more than 200nm, namely 1/10 with the thickness not more than D2 is within the range of 1 nm-200 nm. Wherein the upper limit of the thickness D3 of the protective layer can be 200nm, 180nm, 150nm, 120nm, 100nm, 80nm, 60nm, 55nm, 50nm, 45nm, 40nm, 30nm and 20nm, and the lower limit of the thickness D3 of the protective layer can be 1nm, 2nm, 5nm, 8nm, 10nm, 12nm, 15nm and 18 nm; the range of the thickness D3 of the protective layer may consist of any value of the upper or lower limit. If the protective layer is too thin, it is not sufficient to function to protect the conductive layer; too thick a protective layer may reduce the gravimetric and volumetric energy densities of the battery. Preferably, 10nm < D3 < 50 nm.

From the viewpoint that the protective layer occupies the entire thickness of the conductive layer, it is preferable that D3 satisfies: 1/2000D2 is not less than D3 not more than 1/10D2, namely the thickness is 1/2000-1/10 of D2. More preferably, D3 satisfies: 1/1000D2 is not less than D3 is not less than 1/10D 2.

The protective layer may be formed on the conductive layer body by vapor deposition, in-situ formation, coating, or the like. The Vapor Deposition method is preferably Physical Vapor Deposition (PVD); the physical vapor deposition method is preferably at least one of an evaporation method and a sputtering method; the Evaporation method is preferably at least one of vacuum Evaporation (vacuum Evaporation), Thermal Evaporation (Thermal Evaporation) and Electron Beam Evaporation (EBEM), and the sputtering method is preferably Magnetron sputtering (Magnetron sputtering). The in-situ formation method is preferably an in-situ passivation method, i.e., a method of forming a metal oxide passivation layer in situ on a metal surface. The coating method is preferably one of roll coating, extrusion coating, blade coating, gravure coating, and the like.

[ insulating layer ]

In the current collector of the embodiment of the application, the insulating layer mainly plays a role in supporting and protecting the conductive layer, the thickness of the insulating layer is D1, and D1 satisfies that D1 is less than or equal to 1 μm and less than or equal to 20 μm. If the insulating layer is too thin, the insulating layer is easy to break in the processes of pole piece processing technology and the like; too thick, the volumetric energy density of the battery using the current collector may be reduced.

Wherein the upper limit of the thickness D1 of the insulating layer can be 20 μm, 15 μm, 12 μm, 10 μm, 8 μm, and the lower limit of the thickness D1 of the conductive layer can be 1 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm; the range of the thickness D1 of the insulating layer may consist of any value of the upper or lower limit. Preferably 2 μm. ltoreq. D1. ltoreq.10 μm, more preferably 2 μm. ltoreq. D1. ltoreq.6 μm.

Optionally, the material of the insulating layer is selected from one of an organic polymer insulating material, an inorganic insulating material, and a composite material. Further preferably, the composite material is composed of an organic polymer insulating material and an inorganic insulating material.

Wherein the organic polymer insulating material is selected from Polyamide (PA), Polyethylene terephthalate (PET), Polyimide (PI), Polyethylene (PE), Polypropylene (PP), Polystyrene (PS), Polyvinyl chloride (PVC), Acrylonitrile-butadiene-styrene copolymer (ABS), Polybutylene terephthalate (PBT), polyterephthalamide (PPA), epoxy resin (epoxy resin), Polypropylene (PPE), Polyformylamide (POM), phenolic resin (PTFE), Polytetrafluoroethylene (PTFE), Polyformaldehyde (Polyformaldehyde) and Polyformaldehyde (Polyformaldehyde), PVDF for short) and Polycarbonate (PC for short).

The inorganic insulating material is preferably alumina (Al)₂O₃) Silicon carbide (SiC), silicon dioxide (SiO)₂) At least one of;

the composite is preferably at least one of epoxy resin glass fiber reinforced composite material and polyester resin glass fiber reinforced composite material.

Because the density of insulating layer is usually less than the metal, consequently this application mass flow body, when promoting battery security performance, can also promote the weight energy density of battery. And because the insulating layer can play good bearing and protection effect to the conducting layer that is located its surface, therefore the common pole piece fracture phenomenon among the traditional mass flow body is difficult for producing.

A second aspect of the embodiments of the present application provides a pole piece, including the current collector of the first aspect of the embodiments of the present application and an electrode active material layer formed on a surface of the current collector.

Fig. 17 and 18 are schematic structural diagrams of a positive electrode sheet according to an embodiment of the present application, and as shown in fig. 17 and 18, the positive electrode sheet 1 includes a positive electrode current collector 10 according to the present application and a positive electrode active material layer 11 formed on a surface of the positive electrode current collector 10, and the positive electrode current collector 10 includes a positive electrode insulating layer 101 and a positive electrode conductive layer 102.

Fig. 19 and 20 are schematic structural diagrams of a negative electrode tab of an embodiment of the present application, and as shown in fig. 19 and 20, the negative electrode tab 2 includes a negative electrode collector 20 of the present application and a negative active material layer 21 formed on a surface of the negative electrode collector 20, and the negative electrode collector 20 includes a negative electrode insulating layer 201 and a negative electrode conductive layer 202.

When the conductive layers are arranged on the two sides of the insulating layer, the active substances are coated on the two sides of the current collector, and the prepared positive pole piece and the prepared negative pole piece are respectively shown in fig. 17 and 19 and can be directly applied to a battery. When the single surface of the insulating layer is provided with the conductive layer, the single surface of the current collector is coated with the active substance, and the prepared positive pole piece and the prepared negative pole piece are respectively shown in fig. 18 and 20 and can be folded to be applied to the battery.

A third aspect of the embodiments of the present application provides a battery, including a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte.

The positive pole piece and/or the negative pole piece are/is the pole pieces in the embodiment of the application. The battery of the application can be of a winding type and also can be of a laminated type. The battery of the present application may be one of a lithium ion secondary battery, a lithium primary battery, a sodium ion battery, and a magnesium ion battery. But is not limited thereto.

Further, an embodiment of the present application further provides a battery, which includes a positive electrode plate, a diaphragm, a negative electrode plate, and an electrolyte, where only the positive electrode plate is the positive electrode plate in the above embodiment.

Preferably, the positive electrode plate of the battery in the embodiment of the present application adopts the electrode plate of the present application. Because the aluminum content in the conventional positive current collector is high, when a short circuit occurs under the abnormal condition of the battery, the heat generated at the short circuit point can cause severe thermite reaction, so that a large amount of heat is generated and the battery is caused to explode and other accidents, therefore, when the positive pole piece of the battery adopts the pole piece of the application, the thermite reaction can be avoided due to the fact that the amount of aluminum in the positive current collector is greatly reduced, and the safety performance of the battery is obviously improved.

The abnormal condition of the battery is simulated by adopting a nail penetration experiment so as to observe the change of the battery after the nail penetration. Fig. 21 is a schematic diagram of a one-time nail penetration experiment of the battery according to the embodiment of the present application. For simplicity, the drawing shows only the case where the nail 4 penetrates one positive electrode tab 1, one separator 3 and one negative electrode tab 2 of the battery. It should be noted that the actual nailing experiment is to make the nail 4 penetrate the whole battery, and generally comprises a plurality of layers of the positive pole piece 1, the separator 3 and the negative pole piece 2. According to fig. 21, after the short circuit of the battery occurs due to the through-pins, the short-circuit current is greatly reduced, and the heat generated by the short circuit is controlled in the range which can be completely absorbed by the battery, so that the heat generated at the position of the short circuit can be completely absorbed by the battery, the temperature rise of the battery is small, the influence of the short circuit damage on the battery can be limited to the through-pin position, only the point open circuit is formed, and the normal work of the battery in a short time is not influenced.

In addition, the present application finds, through a large number of experiments, that the larger the capacity of the battery, the smaller the internal resistance of the battery, and the worse the safety performance of the battery, that is, the battery capacity (Cap) and the internal resistance (r) of the battery are in an inverse proportion relationship:

r＝A/Cap

where r represents the internal resistance of the battery, Cap represents the capacity of the battery, and A is a coefficient.

The battery capacity Cap is the theoretical capacity of the battery, and is usually the theoretical capacity of the positive electrode plate of the battery.

r can be obtained by testing an internal resistance meter.

For a conventional lithium ion secondary battery composed of a conventional positive electrode tab and a conventional negative electrode tab, basically all conventional lithium ion secondary batteries generate different degrees of smoke, fire, explosion and the like when internal short circuit occurs under abnormal conditions.

The battery of the embodiment of the present application can have a larger a value because it has a relatively larger internal resistance of the battery under the condition of the same battery capacity.

For the battery of the embodiment of the application, when the coefficient A satisfies 25 Ah.mOmega not more than A not more than 400 Ah.mOmega, the battery can have good electrochemical performance and good safety performance.

When the value of a is too large, the battery is not practical because electrochemical performance is deteriorated due to excessive internal resistance.

When the value of A is too small, the temperature rise is too high when the battery is subjected to internal short circuit, and the safety performance of the battery is reduced.

More preferably, the coefficient A satisfies 30 Ah.mOmega.ltoreq.A.ltoreq.200 Ah.mOmega; more preferably, the coefficient A satisfies 40 Ah.mOmega.ltoreq.A.ltoreq.150 Ah.mOmega.

The embodiment of the application also relates to the application of the current collector in preparing a battery which only forms a point open circuit to protect itself when the current collector is subjected to an abnormal condition causing short circuit. In the application, when the battery can limit the influence of short-circuit damage on the battery to a point range, the characteristic that the battery is normally used in a short time is not influenced, and the point is called as point disconnection.

On the other hand, the embodiment of the application also relates to the application of the current collector as the current collector of the battery which only forms point open circuit when the current collector is subjected to the abnormal condition causing short circuit.

Preferably, the abnormal conditions causing the short circuit include impact, extrusion, penetration of foreign matter, etc., and the abnormal conditions causing the short circuit in the damage process are all caused by electrically connecting the positive electrode and the negative electrode with a material having certain conductivity, so the abnormal conditions are collectively referred to as a through-pin in the present application. And the abnormal condition of the battery is simulated through a nail penetration experiment in the specific embodiment of the application.

Examples

1. Preparing a current collector:

selecting an insulating layer with a certain thickness, forming a conductive layer with a certain thickness on the surface of the insulating layer through vacuum evaporation, mechanical rolling or bonding, and measuring the normal-temperature film resistance of the conductive layer.

Wherein,

(1) the formation conditions of the vacuum deposition method were as follows: and (2) placing the insulating layer subjected to surface cleaning treatment in a vacuum plating chamber, melting and evaporating the high-purity metal wire in the metal evaporation chamber at a high temperature of 1600-2000 ℃, passing the evaporated metal through a cooling system in the vacuum plating chamber, and finally depositing the metal on the surface of the insulating layer to form a conductive layer.

(2) The forming conditions of the mechanical rolling system are as follows: the foil of the conductive layer material is placed in a mechanical roller, rolled to a predetermined thickness by applying a pressure of 20t to 40t, then placed on the surface of the insulating layer subjected to the surface cleaning treatment, and finally placed in a mechanical roller, and tightly bonded by applying a pressure of 30t to 50 t.

(3) The conditions for forming the bonding pattern were as follows: placing the foil of conductive layer material in a mechanical roller, and rolling it to a predetermined thickness by applying a pressure of 20t to 40 t; then coating a mixed solution of PVDF and NMP on the surface of the insulating layer subjected to surface cleaning treatment; and finally, adhering the conductive layer with the preset thickness on the surface of the insulating layer, and drying at 100 ℃.

(4) The method for measuring the film resistance at the normal temperature comprises the following steps:

RTS-9 type double-electric-test four-probe tester is used, and the test environment is as follows: the normal temperature is 23 +/-2 ℃, and the relative humidity is less than or equal to 65 percent. During testing, the surface of a material to be tested is cleaned, then the material to be tested is horizontally placed on a test bench, four probes are put down to enable the probes to be in good contact with the surface of the material to be tested, then the current range of the material is calibrated in an automatic test mode, thin film sheet resistance measurement is carried out under the proper current range, and 8-10 data points of the same sample are collected to be used as data measurement accuracy and error analysis.

Specific parameters of the current collectors and the pole pieces thereof in the examples and comparative examples are shown in table 1.

2. Preparation of current collector with protective layer:

the current collector with the protective layer is prepared in several ways:

(1) firstly, arranging a protective layer on the surface of an insulating layer by a vapor deposition method or a coating method, and then forming a conductive layer body with a certain thickness on the surface of the insulating layer with the protective layer by a vacuum evaporation method, a mechanical rolling method or a bonding method so as to prepare a current collector with the protective layer (the protective layer is positioned between the insulating layer and the conductive layer body); in addition, on the basis, another protective layer can be formed on the surface of the conductive layer body, which is far away from the insulating layer, by a vapor deposition method, an in-situ formation method or a coating method so as to prepare a current collector with the protective layer (the protective layer is positioned on two opposite surfaces of the conductive layer body);

(2) forming a protective layer on one surface of a conductive layer body by a vapor deposition method, an in-situ formation method or a coating method, and then arranging the conductive layer body with the protective layer on the surface of an insulating layer in a mechanical rolling or bonding manner, wherein the protective layer is arranged between the insulating layer and the conductive layer body so as to prepare a current collector with the protective layer (the protective layer is arranged between the insulating layer and the conductive layer body); in addition, on the basis, another protective layer can be formed on the surface of the conductive layer body, which is far away from the insulating layer, by a vapor deposition method, an in-situ formation method or a coating method so as to prepare a current collector with the protective layer (the protective layer is positioned on two opposite surfaces of the conductive layer body);

(3) forming a protective layer on one surface of the conductive layer body by a vapor deposition method, an in-situ formation method or a coating method, and then arranging the conductive layer body with the protective layer on the surface of the insulating layer in a mechanical rolling or bonding manner, wherein the protective layer is arranged on the surface of the conductive layer body, which is far away from the insulating layer, so as to prepare a current collector with the protective layer (the protective layer is arranged on the surface of the conductive layer body, which is far away from the insulating layer);

(4) firstly, forming protective layers on two surfaces of a conductive layer body by a vapor deposition method, an in-situ forming method or a coating method, and then arranging the conductive layer body with the protective layers on the surface of an insulating layer by a mechanical rolling or bonding method to prepare current collectors with the protective layers (the protective layers are positioned on two opposite surfaces of the conductive layer body);

(5) on the basis of the preparation of the current collector, another protective layer is formed on the surface of the conductive layer body, which is far away from the insulating layer, by a vapor deposition method, an in-situ formation method or a coating method, so as to prepare the current collector with the protective layer (the protective layer is positioned on the surface of the conductive layer body, which is far away from the insulating layer).

In the preparation examples, the vapor deposition method adopts a vacuum evaporation method, the in-situ formation method adopts an in-situ passivation method, and the coating method adopts a scraper coating method.

The formation conditions of the vacuum deposition method were as follows: and (3) placing the sample subjected to surface cleaning treatment in a vacuum plating chamber, melting and evaporating the protective layer material in the evaporation chamber at a high temperature of 1600-2000 ℃, passing the evaporated protective layer material through a cooling system in the vacuum plating chamber, and finally depositing the evaporated protective layer material on the surface of the sample to form a protective layer.

The in-situ passivation method is formed under the following conditions: and (3) placing the conductive layer body in a high-temperature oxidation environment, controlling the temperature to be 160-250 ℃, and simultaneously maintaining oxygen supply in the high-temperature environment for 30min, thereby forming a protective layer of metal oxides.

The formation conditions of the gravure coating method were as follows: stirring and mixing a protective layer material and NMP, coating slurry (solid content is 20-75%) of the protective layer material on the surface of a sample, controlling the coating thickness by using a gravure roller, and finally drying at 100-130 ℃.

The specific parameters of the prepared current collector with the protective layer and the pole piece thereof are shown in table 2.

3. Preparing a pole piece:

coating positive electrode slurry or negative electrode slurry on the surface of a current collector by a conventional battery coating process, and drying at 100 ℃ to obtain a positive electrode piece or a negative electrode piece.

Conventional positive electrode piece: the current collector is an Al foil having a thickness of 12 μm, and the electrode active material layer is a ternary (NCM) material layer having a certain thickness.

Conventional negative pole pieces: the current collector is a Cu foil having a thickness of 8 μm, and the electrode active material layer is a graphite material layer having a certain thickness.

In table 1, there is no protective layer in the current collectors of pole piece # 1 to pole piece # 10; the pole pieces in table 2 are provided with protective layers, where "pole piece 3-1 #" indicates that the conductive layer body is the same as the conductive layer of pole piece 3#, and so on, "pole piece 6-4 #" indicates that the conductive layer body is the same as the conductive layer of pole piece 6#, and so on.

4. Preparing a battery:

the positive pole piece (compacted density: 3.4 g/cm) is processed by the conventional battery manufacturing process³) PP/PE/PP separator and negative electrode plate (compacted density: 1.6g/cm³) Winding the raw materials together to form a naked electric core, then placing the naked electric core into a battery shell, and injecting electrolyte (EC: EMC volume ratio of 3:7, LiPF)₆1mol/L), followed by sealing, chemical conversion and other steps, to finally obtain the lithium ion secondary battery.

Specific compositions of the batteries fabricated in the examples of the present application and the comparative batteries are shown in table 3.

TABLE 1

Table 2:

wherein, the protective layer 1 refers to a protective layer located on the surface (i.e. the lower surface) of the conductive layer body facing the insulating layer, and the thickness thereof is D3'; protective layer 2 refers to a protective layer on the side of the conductive layer body facing away from the insulating layer (i.e. the upper surface), with a thickness D3 "; "/" indicates no protective layer.

TABLE 3

Wherein, by further increasing the number of winding layers of the cell, the batteries 12# and 13# with further improved capacity are prepared.

Experimental example:

1. the battery testing method comprises the following steps:

the cycle life test of the lithium ion battery is carried out by the following specific test method:

charging and discharging the lithium ion battery at two temperatures of 25 ℃ and 45 ℃ respectively, namely charging to 4.2V by using a current of 1C, then discharging to 2.8V by using a current of 1C, and recording the discharge capacity of the first week; then, the battery was subjected to a 1C/1C charge-discharge cycle for 1000 weeks, the discharge capacity of the battery at the 1000 th week was recorded, and the discharge capacity at the 1000 th week was divided by the discharge capacity at the first week to obtain the capacity retention rate at the 1000 th week.

The results of the experiment are shown in table 4.

2. Testing of internal resistance of battery

The test is carried out by using an internal resistance instrument (model is HIOKI-BT3562), and the test environment is as follows: normal temperature 23 plus or minus 2 ℃. Before testing, short-circuit calibration resistance at the positive and negative ends of the internal resistance instrument is zero; during testing, the positive and negative electrode lugs of the lithium ion battery to be tested are cleaned, and then the positive and negative testing ends of the internal resistance instrument are respectively connected to the positive and negative electrode lugs of the lithium ion battery to be tested and recorded. And the coefficient a is calculated according to the formula r ═ a/Cap.

3. The experimental method and the test method of the one-time nail penetration experiment and the six-time continuous nail penetration experiment comprise the following steps:

(1) primary nail penetration experiment: after the battery is fully charged, fixing, penetrating a steel needle with the diameter of 6mm through the battery at the speed of 25mm/s at normal temperature, retaining the steel needle in the battery, completing nail penetration, and then observing and testing.

(2) Six nailing experiments: after the battery is fully charged, fixing, enabling six steel needles with the diameter of 6mm to penetrate through the battery at the speed of 25mm/s at normal temperature, retaining the steel needles in the battery, completing nail penetration, and observing and testing.

(3) Testing the temperature of the battery: and (3) respectively attaching temperature sensing lines to the geometric centers of the needling surface and the back surface of the battery to be nailed by using a multi-path thermodetector, carrying out five-minute battery temperature tracking test after nailing is finished, and then recording the temperature of the battery at five minutes.

(4) Testing of the battery voltage: and connecting the positive electrode and the negative electrode of the battery to be nailed to the measuring end of the internal resistance instrument, carrying out a battery voltage tracking test for five minutes after the nailing is finished, and recording the voltage of the battery for five minutes.

The data of the temperature and voltage of the battery are recorded as shown in table 5.

TABLE 4

TABLE 5

Note: "N/A" means that a steel needle penetrates into the battery to instantaneously cause thermal runaway and damage.

TABLE 6

From the results in table 4, the cycle life of the battery using the current collector of the example of the present application was good compared to battery # 1 using the conventional positive electrode tab and the conventional negative electrode tab, and was comparable to the cycle performance of the conventional battery. This demonstrates that the current collectors of the examples of the present application do not have a significant adverse effect on the resulting pole pieces and cells. Particularly, the capacity retention rate of the battery made of the current collector with the protective layer is further improved, which shows that the reliability of the battery is better.

In addition, the current collector of the embodiment of the application can greatly improve the safety performance of the lithium ion battery. The cell temperature curves of cell 1# and cell 4# with time are shown in fig. 22, and the voltage curves with time are shown in fig. 23. From the results in table 5 and fig. 22 and 23, in the battery 1# without the current collector of the embodiment of the present application, the battery temperature suddenly rises by several hundred degrees and the voltage suddenly drops to zero at the time of nailing, which indicates that the battery has an internal short circuit at the time of nailing, generates a large amount of heat, and the battery has thermal runaway and damage at the time of nailing, and cannot continue to operate; and because the battery has thermal runaway and is destroyed at the moment after the first steel needle penetrates into the battery, the six-steel-needle continuous nail penetration experiment cannot be carried out on the battery.

And the lithium ion battery who has adopted the mass flow body of this application embodiment, especially when the mass flow body of this application embodiment is anodal mass flow body, no matter carry out a drift nail experiment or six times of continuous drift nail experiments to it, battery temperature rise all can be controlled about 10 ℃ or below 10 ℃ basically, and voltage remains stable basically, and electric core can normally work.

The data in table 6 show that the increase of the resistance of the current collector is beneficial to improving the internal resistance r of the battery, so that the coefficient A value is improved, and the safety performance of the battery is improved; especially when the capacity of the battery is larger, the resistance of the current collector is increased, so that the internal resistance r of the battery can be effectively improved, the coefficient A value is kept in a higher numerical range, and the safety performance of the battery is improved.

Therefore, under the condition that the battery is internally short-circuited, the current collector of the embodiment of the application can greatly reduce the heat generated by short circuit, so that the safety performance of the battery is improved; in addition, the influence of short-circuit damage on the battery can be limited to a 'point' range, and only 'point open circuit' is formed, so that the normal operation of the battery in a short time is not influenced.

Although the present application has been described with reference to preferred embodiments, it is not intended to limit the scope of the claims, and many possible variations and modifications may be made by one skilled in the art without departing from the spirit of the application.

Claims

1. A battery comprises a positive pole piece, a diaphragm, a negative pole piece and electrolyte, and is characterized in that the positive pole piece and/or the negative pole piece comprises a current collector and an electrode active material layer formed on the surface of the current collector;

the current collector comprises an insulating layer and a conductive layer,

the insulating layer is used for bearing the conducting layer;

the conductive layer is used for bearing an electrode active material layer and is positioned on at least one surface of the insulating layer,

the conductive layer comprises a conductive layer body and a protective layer arranged on at least one surface of the conductive layer body, the protective layer is made of nickel oxide, and the normal-temperature thin-film resistor R of the conductive layer_SSatisfies the following conditions: r is more than or equal to 0.01 omega/□_S≤0.15Ω/□；

r represents the internal resistance of the battery, Cap represents the capacity of the battery, and the relationship between r and Cap satisfies:

25Ah·mΩ≤r×Cap≤400Ah·mΩ。

2. the battery of claim 1, wherein the conductive layer has a room temperature sheet resistance R_SSatisfies the following conditions: r is more than or equal to 0.02 omega/□_S≤0.1Ω/□。

3. The battery of claim 1, wherein the conductive layer has a thickness D2, D2 being: d2 is more than or equal to 300nm and less than or equal to 2 mu m.

4. The battery of claim 3, wherein 500nm ≦ D2 ≦ 1.5 μm.

5. The battery of claim 1, wherein the insulating layer has a thickness of D1, D1 satisfies: d1 is more than or equal to 1 mu m and less than or equal to 20 mu m.

6. The battery of claim 5, wherein 2 μm D1 μm 10 μm.

7. The battery of claim 6, wherein 2 μm D1 μm 6 μm.

8. The battery according to claim 1, wherein the conductive layer is made of at least one material selected from a metal conductive material and a carbon-based conductive material.

9. The battery according to claim 8, wherein the metal conductive material is at least one selected from the group consisting of aluminum, copper, nickel, titanium, silver, nickel-copper alloy, and aluminum-zirconium alloy, and the carbon-based conductive material is at least one selected from the group consisting of graphite, acetylene black, graphene, and carbon nanotubes.

10. The battery according to claim 1, wherein the insulating layer is made of at least one material selected from the group consisting of an organic polymer insulating material, an inorganic insulating material, and a composite material.

11. The battery according to claim 10, wherein the organic polymer insulating material is selected from at least one of polyamide, polyester terephthalate, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polybutylene terephthalate, poly (paraphenylene terephthalamide), polypropylene, polyoxymethylene, epoxy resin, phenol resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, polycarbonate;

the inorganic insulating material is selected from at least one of alumina, silicon carbide and silicon dioxide;

the composite material is at least one of epoxy resin glass fiber reinforced composite material and polyester resin glass fiber reinforced composite material.

12. The battery of claim 1, wherein the material of the conductive layer body is selected from at least one of a metal conductive material, a carbon-based conductive material; the metal conductive material is selected from at least one of aluminum, copper, nickel, titanium, silver, nickel-copper alloy and aluminum-zirconium alloy, and the carbon-based conductive material is selected from at least one of graphite, acetylene black, graphene and carbon nano tubes.

13. The battery of claim 1, wherein the protective layer is disposed only on a side of the conductive layer body facing away from the insulating layer, or the protective layer is disposed only on a side of the conductive layer body facing the insulating layer, or the protective layer is disposed on opposite surfaces of the conductive layer body.

14. The battery of claim 1, wherein the protective layer has a thickness of D3, D3 satisfies: d3 is not less than 1/10D2 and D3 is not less than 1nm and not more than 200 nm.

15. The battery of claim 14, wherein 10nm ≦ D3 ≦ 50 nm.

16. The battery of claim 1, wherein only the current collector forms a point break when the battery is subjected to an abnormal condition that induces a short circuit.

17. The battery of claim 16, wherein the current collector is a positive current collector.

18. The battery of claim 16, wherein the short circuit inducing abnormality is a nail.